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Re: [Phys-l] Galaxies and clustering in astronomy



On 5/14/2011 2:27 AM, alex brown wrote:
Hello All,

I could not find anything about this in the archive so thought I'd ask here.

I have a 3d array of points with each point having an "intensity." I wish to group points into "galaxies," and wonder what algorithms are used in astronom? Does anyon here have any experience in this? I am looking for something that would be quick and does not need to be 100% accurate.
As an aside the actual problem is...... circle recognition in an image from a fabry perot. I have used hough transform and my 3d array is in "hough space." The array is sparse and thus I thought it is analogous to the problem of stars and assigning them to galaxies. I don't want to reinvent the wheel so....

Thanks for any suggestions
Alex
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Not sure how helpful it is: but a grey scale image can be processed in the Matlab application to
provide circle center locations and radii, see this:

<http://www.mathworks.com/matlabcentral/fileexchange/9168-detect-circles-with-various-radii-in-grayscale-image-via-hough-transform>

*http://tinyurl.com/42n7h3e*

Brian W